Fix some sloppy code in context hierarchy support

* The SpringApplicationBuilder was registering the parent context initializer
twice (not really a problem, but confusing if you are debugging).

* ParentContextApplicationContextInitializer itself should have been
checking that the current context is not the parent

* The EventPublishingRunListener as a result needs to call
setApplicationContext on any listeners that are AplicationContextAware

* ParentContextCloserApplicationListener can ensure that there is
only one of its kind per application context by implementing hashCode
and equals

Fixes gh-1142

Author: Dave Syer

spring-boot/src/main/java/org/springframework/boot/builder/ParentContextApplicationContextInitializer.java

@@ -53,8 +53,10 @@ public int getOrder() {
 
 	@Override
 	public void initialize(ConfigurableApplicationContext applicationContext) {
-		applicationContext.setParent(this.parent);
-		applicationContext.addApplicationListener(EventPublisher.INSTANCE);
+		if (applicationContext != this.parent) {
+			applicationContext.setParent(this.parent);
+			applicationContext.addApplicationListener(EventPublisher.INSTANCE);
+		}
 	}
 
 	private static class EventPublisher implements
@@ -70,7 +72,8 @@ public int getOrder() {
 		@Override
 		public void onApplicationEvent(ContextRefreshedEvent event) {
 			ApplicationContext context = event.getApplicationContext();
-			if (context instanceof ConfigurableApplicationContext) {
+			if (context instanceof ConfigurableApplicationContext
+					&& context == event.getSource()) {
 				context.publishEvent(new ParentContextAvailableEvent(
 						(ConfigurableApplicationContext) context));
 			}

spring-boot/src/main/java/org/springframework/boot/builder/ParentContextCloserApplicationListener.java

@@ -18,7 +18,10 @@
 
 import java.lang.ref.WeakReference;
 
+import org.springframework.beans.BeansException;
 import org.springframework.boot.builder.ParentContextApplicationContextInitializer.ParentContextAvailableEvent;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.event.ContextClosedEvent;
@@ -33,11 +36,21 @@
  * @author Eric Bottard
  */
 public class ParentContextCloserApplicationListener implements
-		ApplicationListener<ParentContextAvailableEvent>, Ordered {
+		ApplicationListener<ParentContextAvailableEvent>, ApplicationContextAware,
+		Ordered {
+
+	private int order = Ordered.LOWEST_PRECEDENCE - 10;
+
+	private ApplicationContext context;
 
 	@Override
 	public int getOrder() {
-		return Ordered.LOWEST_PRECEDENCE - 10;
+		return this.order;
+	}
+
+	@Override
+	public void setApplicationContext(ApplicationContext context) throws BeansException {
+		this.context = context;
 	}
 
 	@Override
@@ -46,10 +59,12 @@ public void onApplicationEvent(ParentContextAvailableEvent event) {
 	}
 
 	private void maybeInstallListenerInParent(ConfigurableApplicationContext child) {
-		if (child.getParent() instanceof ConfigurableApplicationContext) {
-			ConfigurableApplicationContext parent = (ConfigurableApplicationContext) child
-					.getParent();
-			parent.addApplicationListener(createContextCloserListener(child));
+		if (child == this.context) {
+			if (child.getParent() instanceof ConfigurableApplicationContext) {
+				ConfigurableApplicationContext parent = (ConfigurableApplicationContext) child
+						.getParent();
+				parent.addApplicationListener(createContextCloserListener(child));
+			}
 		}
 	}
 
@@ -82,6 +97,35 @@ public void onApplicationEvent(ContextClosedEvent event) {
 			}
 		}
 
+		@Override
+		public int hashCode() {
+			final int prime = 31;
+			int result = 1;
+			result = prime
+					* result
+					+ ((this.childContext.get() == null) ? 0 : this.childContext.get()
+							.hashCode());
+			return result;
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj)
+				return true;
+			if (obj == null)
+				return false;
+			if (getClass() != obj.getClass())
+				return false;
+			ContextCloserListener other = (ContextCloserListener) obj;
+			if (this.childContext.get() == null) {
+				if (other.childContext.get() != null)
+					return false;
+			}
+			else if (!this.childContext.get().equals(other.childContext.get()))
+				return false;
+			return true;
+		}
+
 	}
 
 }

spring-boot/src/main/java/org/springframework/boot/builder/SpringApplicationBuilder.java

@@ -215,7 +215,6 @@ public SpringApplicationBuilder parent(ConfigurableApplicationContext parent) {
 		this.parent = new SpringApplicationBuilder();
 		this.parent.context = parent;
 		this.parent.running.set(true);
-		initializers(new ParentContextApplicationContextInitializer(parent));
 		return this;
 	}
 

spring-boot/src/main/java/org/springframework/boot/context/event/EventPublishingRunListener.java

@@ -19,6 +19,7 @@
 import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.SpringApplicationRunListener;
+import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.event.ApplicationEventMulticaster;
@@ -78,6 +79,9 @@ private void registerApplicationEventMulticaster(
 	@Override
 	public void contextLoaded(ConfigurableApplicationContext context) {
 		for (ApplicationListener<?> listener : this.application.getListeners()) {
+			if (listener instanceof ApplicationContextAware) {
+				((ApplicationContextAware) listener).setApplicationContext(context);
+			}
 			context.addApplicationListener(listener);
 		}
 		publishEvent(new ApplicationPreparedEvent(this.application, this.args, context));